Sharing biosignals during social interaction modulates psychophysiological states and perceived interpersonal closeness

Advances in digital technology have made physiological signals such as electrocardiography (ECG) and electrodermal activity (EDA) increasingly accessible, enabling previously covert bodily states to be shared in real time during social exchanges. Recent work, primarily qualitative, suggests that biosignal sharing can modulate social interaction, yet quantitative evidence on its psychophysiological impact remains limited. Here, we investigated whether biosignal sharing during social interaction, and in particular the reciprocity of information exchange, modulates psychophysiological responses. We present data from 18 sex-matched dyads (N = 36) of strangers, whose ECG and EDA were recorded while they engaged in nonverbal face-to-face interaction. Participants shared their heart rate and skin conductance levels (displayed on a monitor) either unidirectionally, bidirectionally, or not at all. We examined the effects of biosignal sharing on indices of autonomic nervous system activity (including RMSSD, skin conductance level, and the number and amplitude of skin conductance responses) and related these measures to psychometric assessments of empathic traits, social interaction anxiety, perceived scrutiny, and interpersonal closeness. Bidirectional biosignal sharing significantly reduced the number of skin conductance responses compared to both face-to-face interaction without sharing and unidirectional sharing. Moreover, greater reductions in sympathetic activation during bidirectional sharing were associated with larger increases in perceived interpersonal closeness. Correlational analyses further indicated that perceived scrutiny was linked to heightened arousal and reduced closeness. Our findings advance the understanding of the physiological and relational impact of biosignal sharing, with direct implications for the design of social computing systems and computer-mediated interactions.